Adding leveled completion options to activity completion would allow teachers to track progress toward a goal rather than simply log that it's been completed. It would also augment their ability to award badges for course participation. For example:
I want to create a forum where a user is given badges for participation in a forum as follows:
10 posts = Little League Forum Poster Badge
20 posts = Minor League Forum Poster Badge
40 posts = Major League Forum Poster Badge
As it is currently set up, I can only award a badge for activity completion, which is restricted to one completion per activity. This improvement would allow me to award a "level 1 complete when condition A is met," a "level 2 complete when condition B is met," "level 3 complete when condition C is met," and so on, such that users could be awarded badges (or anything else that's being tracked through completion) progressively as they continually participate in an activity.